The American inventor perfected the electric light bulb and helped flick the switch on increased productivity in the industrial age. But he also gave rise to round-the-clock work shifts that throw circadian rhythms into a whirl.

Former Windsor filmmaker Michael McNamara examines the effect artificial light is having on our health in a documentary, Lights Out!, to air this Thursday at 8 p.m. on CBC-TV’s The Nature of Things.

“It has reached epidemic levels,” said McNamara. “Shift workers are at risk for all sorts of diseases becaus

Michael McNamara

e of lack of sleep.”

The root cause is the lack of naturally produced melatonin in those who are exposed to too much light. Melatonin is a hormone secreted in the brain which induces sleep when light levels decrease.

The effects of melatonin on general health are still open to debate, but many scientists believe it can reduce the risk of cancer and heart disease. Low levels have also been associated with weight gain.

McNamara said 21 per cent of Canadians work irregular shifts, and in a blue-collar community like Winds

or that percentage is likely higher. That’s why he brought his cameras to Windsor earlier this year to film hotel

workers, taxi drivers and dispatchers, and even early morning CKLW newsman Rob Shervill.

Statistics Canada suggests the problem is exacerbated by the tendency of shift workers to suppress sleep in order to make more efficient use of waking hours.

McNamara’s interest in the adverse effects of light arose during research for his award-winning feature documentary, Acquainted With the Night.

Lights Out! is the first documentary McNamara’s Toronto-based Markham Street Films has produced for The Nature of Things.

“We don’t do a lot of straight scientific documentaries,” he said. “But this was a project that interested us because of its message.”

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